#include    <stdio.h>
    #include    <stdlib.h>
    #include    <unistd.h>

    int main()
    {
        int fork_rv;

        printf("Before: my pid is %d\n", getpid());

        fork_rv = fork();       /* create new process   */

        if ( fork_rv == -1 )        /* check for error  */
            perror("fork");

        else if ( fork_rv == 0 ){ 
            printf("I am the child.  my pid=%d\n", getpid());
            printf("parent pid= %d, my pid=%d\n", getppid(), getpid());
            exit(0);
        }

        else{
            printf("I am the parent. my child is %d\n", fork_rv);
            sleep(10);
            exit(0);
        }

        return 0;
    }